Lapping device, apparatus, and method



April 1939- v H. s. INDGE ET AL 2,153,521

' LAPPLNG DEVICE, APPARATUS. AND METHOD Filed Feb. 5, 1938 v 7 3mm F1 HERBERT SINDEE Fil. BERT [3. BELDEN Patented Apr. 4, 1939 UNITED STATES LAPPING DEVICE, APPARATUS, AND METHOD Herbert s. Indge, Westboro, and Albert cmden, Worcester, Mass, asslgnors to Norton Company, Worcester, Mass, a corporation of Massachusetts Application February 5, 1938, Serial No. 188,898

1 Claim.

The invention relates to lapping devices, apparatus and methods, and with regard to its more specific features to lapping devices, apparatus and methods for lapping the bores of work pieces.

One object of the invention is to provide a lapping device for lapping the bore of an article to fine precision limits. Another object of the invention is to' provide a lapping device which will readily enter the bore of an article to be lapped and which may be expanded in the bore. Another object of the invention is to provide an improved and facile method of lapping work pieces. Another object of the invention is to provide an eflicient and readily controlled lapping apparatus for lapping the bores of work pieces. Other objects will be' in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts, and in the several steps and relation and order of each of said steps to one or more of the others thereof, all as-will be illustratively described herein, and the scope of the application of which will be indicated in the following claim. r

In the accompanying drawing, showing one of various possible embodiments of the mechanical features of this invention,

Figure l is a front elevation of part of a machine upon which the lap of the invention may be mounted and by which it is operated.

Figure 2 is an axial sectional view of the lap and the spindle upon which it is mounted.

Figure 3 is a cross sectional view, taken on the line 3-3 of Figure ,2.

Referring first to Figure 1, we provide a machine frame ll) of any desired characteristics. Suitablymountedon the machine frame It! is'a motor I I or any other desired driving mechanism. Mounted preferably on the top of the frame Ill is a work. head l2 journalling a spindle Hi. The

' spindle I3 is hollow, as shown in Figures 1 and 2,

and is connected by means of a stuffing box l4 to a pipe l5.

The motor II has an armature shaft It on which is mounted a. pulley l1 and which shaft 1 It extends into a gear pump it, being direct connected to one of the gears thereof and thereby 'drivingthe pump. The pipe I5 is connected to the"discharge, end of the pump l8 while the inlet of the pump I8 is connected by a pipe I9 to a sump"; A pipe 2| connects the pipe l5- to a pressure gauge 22 and a relief valve 23, the opening pressure of which is controlled by a handle 24.

(Cl. t -184.1)

is thus rotated whenever the motor II is energized.

Referring now to Figure-2, the front end of the spindle I 3 is threaded as shown at and a clamping nut 36 is provided to clamp any one of a plurality of laps 31 to the spindle Ill. The lap 31 is shown in Figures 2 and 3 and comprises a. seamless tube of metal having a flange 38 at one end and a non-plane wall 39 at the other end. The central portion of the lap 31 has cylindrical segmental portions 40 shown in Figure 3 which are spaced from depressions M, the latter being connected to the segments 40 by portions 42.

We further provide a table having mounted thereon a work holder 46 which may comprise an anvil 41 and a movable clamping device 48 actuated by a screw 49 controlled by a hand wheel 50. The table 45 is movable on ways 5| on the frame and may be moved by rotating a screw shaft 52 which fits in a nut 53, the screw shaft being turned by a hand wheel 54.

In operating the apparatus, a suitable wor piece W is clamped in the work holder 46 and, a lap 31 having been selected which will fit in the bore of the work piece, the hand wheel 54 is turned to advance the table 45 to carry the work piece to the lap 31, thereby introducing the lap work piece, are maintained substantially cylin-' drlcal. A suitable traverse between work piece and lap may be caused by rotating the hand wheel 54 first in one direction and then in the other.

By means of the lap and apparatus of the invention, lapping or abrading of an article can be achieved on a wide area thereof as distinguished from the slight area. of contact between a grinding wheel and a work piece. Furthermore. varying pressures may be applied during. the lapping operation and if the lap 31 is made ofsteel, a given pressure will expand it a given amount. Thus the ultimate diameter of the bore may be readily controlled.

While we have referred to the device as a lapping device, the apparatus as a. lapping apparatus and the method as a lapping method, it should be understood that a substantial amount ofmaterial may actually be'removed from the work piece thereby, if desired. While the control has been described as hydraulic, so far as certain features of the invention are concerned, we may use pneumatic pressure. The number of segments 40 can be greatly increased if desired or decreased if desired. Furthermore, so far as certain features of the invention are concerned, other shapes of the lapping tool may be adopted. The non-plane portion 39 readily permits expansion at the outer end of the lap and by the use of a traverse, bell mouthing or other distortion of the bore may be avoided.

It will thus be seen that there has been provided by this invention an article, apparatus and method in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

A lapping tool comprising a tube of metal having an opening at one end, a non-plane wall at the other-end, and a central portion comprising a plurality of cylindrical segments joined to depressed portions between the segments.

HERBERT S. INDGE. ALBERT G. BELDEN. 

